Project Background. With the rapid aging of the baby boomer generation, the number of US Veterans at risk for neurodegenerative diseases such as Alzheimer's disease (AD) will continue to grow dramatically. Veterans are an important segment of the aging US population who are at an elevated risk for developing for developing cognitive decline and AD due to military and combat related circumstances and exposures. A top national priority for AD research is to identify the earliest stages of cognitive decline, when preventative treatments might be most effective. In order to effectively address AD in aging Veterans, new inter-disciplinary approaches are needed to identify the earliest signals of cognitive and functional decline, thereby facilitating earlier diagnosis and more effective monitoring and treatment. Project Objectives. The overall goal of this pilot study is to generate preliminary data about the feasibility of a novel assessment approach that integrates passive in- home and mobile technologies to provide practical, low cost, accessible, and noninvasive tools to allow for earlier identification of subtle cognitive and functional changes in aging Veterans. Knowledge gained from proposed study will be used to refine the assessment tools and procedures for a future larger-scale VA study with aging Veterans. The specific aims for this pilot are: Specific Aim 1: Evaluate the feasibility of processes that will be key to the success of larger scale VA studies using a novel ecologically valid assessment approach that integrates ambient in-home and mobile technologies to identify mild cognitive and functional impairments that are not well captured by clinic-based assessment methods. Specific Aim 2: Explore the generalizability of established software algorithms for synthesizing the streams of sensor data into ecologically valid sensor- based cognitive and functional measures with a Veteran sample. Specific Aim 3: Explore established sensor- based everyday cognition measures as tools for detecting MCI in a Veteran sample. Project Methods. This is a quantitative pilot study of 30 Veterans aged 62 and older recruited from the MVAHCS neuropsychology and primary care clinics. Aim 1 will be addressed by having participants complete a baseline clinic visit with validated measures to characterize their cognition, mood, daily functioning, physical health, medical co- morbidities, sleep, and medication taking. Participants will then have 12 months of continuous in-home and mobile data collection through a platform of wireless sensors embedded in common devices, followed by completion of a study exit clinic visit with repeat clinical testing to assess for interval changes. Feasibility of processes that will be key to the success of larger scale VA studies will be examined such as recruitment rates, retention rates, appropriateness of eligibility criteria, acceptability of novel in-home and mobile assessment technologies, understanding study procedures, processing and analysis of continuous sensor data, and technical challenges. To address Aim 2, new and established software algorithms will be applied to the continuous activity data for high precision processing and analysis. From this analysis, ecologically valid sensor-based measures of cognition and function will be computed and the results will be explored relative to results from non-Veteran samples. To address Aim 3, performance on the sensor-based everyday cognition and function measures will be explored in Veterans with intact cognition and in those with mild cognitive impairment (MCI). Project Impact. Ultimately, application of this novel ecologically valid assessment paradigm will have an important positive impact for Veteran health because it will inform Veterans, families, and clinicians about cognitive and functional changes earlier than is possible with current assessment methods, when preventative interventions are most critical. Increased knowledge of the nature of the earliest cognitive and functional changes in MCI gathered in this studies will guide the development of individualized and ecologically relevant interventions to improve Veteran quality of life and maintain functional independence. Project Summary